Research on cognitive complaints & cognitive functioning in patients with Chronic Fatigue Syndrome (CFS): What conclusionscan we draw?

People with chronic fatigue syndrome (CFS) complain of
difficulties with concentration and memory yet studies suggest
that they do not suffer gross deficits in cognitive
functioning. Depressed patients make similar cognitive
complaints, and there is symptomatic overlap between CFS and
depression. Cognitive complaints and depressed mood are
positively correlated in CFS patients but, except on tasks
which are particularly sensitive to depression, cognitive
performance and depression are not. The inconsistency between
cognitive complaints and results of tests of cognitive
functioning resembles that found in other subject groups and
may be due in part to the inappropriate use of laboratory
memory tests for assessing "everyday" cognitive functioning.
Even when cognitive capacity is intact, cognitive performance
may be affected by factors such as arousal, mood, and
strategy. In CFS patients, everyday cognitive tasks may
require excessive processing resources leaving patients with
diminished spare attentional capacity or flexibility.